1. Field of the Invention
The present invention relates in general to a rotary type gas compressor used in refrigerators, room air conditioners and the like and, more particularly, to a device for discharging compressed refrigerant gas from a compression cylinder of the rotary type gas compressor.
2. Description of the Prior Art
As well known to those skilled in the art, air conditioning apparatus, such as a refrigerator or a room air conditioner, typically includes a gas compressor for compressing a refrigerant gas of high temperature and low pressure. This compressor receives the refrigerant gas, which has exchanged the heat with outside air during its flow in an evaporator and changed its liquid state into a gaseous state, and compresses the refrigerant gas and, thereafter, forcibly discharges the compressed refrigerant gas to a continued condenser.
The gas compressors are generally classified into three types, that is piston type compressors, rotary type compressors and recently proposed scroll type compressors, otherwise called screw type compressors.
With reference to FIG. 1, there is shown a construction of a typical rotary type gas compressor. This rotary type gas compressor (hereinbelow, referred to simply as "the rotary compressor") comprises drive means for generation of a rotational force used in compression of refrigerant gas. The rotary compressor further comprises compression means carrying out suction, compression and discharge of the refrigerant gas using the rotational force of the drive means.
The drive means uses a motor which comprises a stator 11 and a rotor 12. The rotor 12 is provided with a rotating shaft 13 at its center.
The compression means comprises an eccentric roller 21, which is eccentrically mounted on the rotor shaft 13 of the motor, and a compression cylinder 22 which receives the roller 21 and defines a compression working chamber therein. In the compression working chamber of the cylinder 22, the roller 21 is eccentrically revolved by the rotational force of the motor and compresses the refrigerant gas sucked into the chamber through a suction port 20.
Upper and lower openings of the compression cylinder are closely covered by first and second flanges 22a and 22b, respectively, thus to achieve the desired hermetic state of the compression working chamber. The suction port 20 communicates with a refrigerant gas accumulator 10 which is in burn connected to an evaporator (not shown).
Turning to FIG. 2, there is shown a construction of a compressed gas discharging device of the above compressor. In the gas discharging device, a retractable vane 23 is radially placed in a wall of the compression cylinder 22 at a position near the suction port 20.
The retractable vane 23 is a rectangular plate having a predetermined thickness as best seen in FIGS. 3a and 3b. This vane 23 is biased by spring means (not shown) at its lower end and always slidably contacts an outer surface of the eccentric roller 21 at its upper end. Hence, the eccentric revolution of the roller 21 causes the vane 23 to be radially elastically reciprocated. This retractable vane 23 also divides the compression working chamber inside the cylinder 22 into two variable chambers, that is, a gas suction chamber and a gas compression chamber.
A refrigerant gas discharge port 25 is formed in a wall of the compression cylinder 22 at a position neighboring the retractable vane 23 in order for discharge of compressed refrigerant gas from the cylinder 22.
This discharge port 25 is opened or closed by an elastic plate valve 26 mounted on the first flange 22a of the cylinder 22.
In operation of the above typical rotary compressor, the motor rotates and generates the rotational force as it is applied with electric power. The rotational force of the motor is transmitted to the eccentric roller 21 through the rotor shaft 13, thus to cause eccentric revolution of the roller 21 in the compression cylinder 22. As a result of the eccentric revolution of the roller 21 in the cylinder 22, the refrigerant gas of the accumulator 10 is introduced into the compression chamber of the cylinder 22 through the suction port 20. This refrigerant gas is, thereafter, compressed due to the eccentric revolution of the roller 21 and discharged from the cylinder 22 through the discharge port 25.
That is, when the eccentric roller 21 is eccentrically revolved clockwise in the cylinder 22 by the rotational force of the motor as shown in FIG. 2, the refrigerant gas of the accumulator 10 is introduced into the gas suction chamber, which is defined at the side of the suction port 20 by the roller 21, the cylinder 22 and the vane 23, through the suction port 20.
The sucked refrigerant gas is in turn compressed in the gas compression chamber due to the eccentric revolution of the roller 21.
When the refrigerant gas in the gas compression chamber is completely compressed, the elastic plate valve 26 is pushed by the pressure of the compressed refrigerant gas and opens the discharge port 25, thus to discharge this compressed refrigerant gas from the cylinder 22.
A continued eccentric revolution of the roller 21 completely retracts the vane 23, thus to integrate the gas suction chamber and the gas compression chamber into one chamber.
At this state, the elastic plate valve 26 closes the discharge port 25 by its own restoring force since the integrated one chamber is filled with newly sucked refrigerant gas which has such low pressure that it can not overcome the elasticity of the plate valve 26.
The newly sucked refrigerant gas of low pressure is in turn compressed in accordance with continued eccentric revolution of the roller 21 and discharged from the cylinder 22 in the same manner as described above.
In operation of the above rotary compressor, the aforementioned suction, compression and discharge of the refrigerant gas is repeated.
However, the typical gas discharging device of the rotary compressor, including the elastic plate valve for opening and closing a gas discharge port, has a problem that there is generated a noise in the opening and closing operation of the plate valve. Another problem of this typical gas discharging device of the rotary compressor is that the use of plate valve makes the construction complex and increases the chance of malfunction of the compressor.